But the main roster guys take up a good amount of time on the show. And we know the main roster guys won't win the belts even if you put them in a title match.

TBH the main roster guys shouldn't be there, I don't really see what the point of them appearing on NXT TV is. If we're talking about people like Percy Watson and Bateman who never appear on the main programs then yeah, but for guys like 3MB and Epico & Primo it's just a waste of time.